So, which medium do they prefer?

Silly me, following instructions again.
   We have usually filed complaints under the Digital Millennium Copyright Act in the US with a printed letter or fax, but when we went to Hostgator’s site, we noticed that they suggested email. ‘To file a copyright infringement claim, please email abuse@hostgator.com after following the steps below in an email’, reads their page.

Hostgator DMCA complaint steps

HostGator requires DMCA notices to be filed via fax or letter. The complaint must include full contact information in the complaint (including phone number). We will call and verify. Email (unless digitally signed by a verified and trusted third party) is not an acceptable medium for legal complaints.  This ticket system has received what appears to be a possible DMCA complaint, but one or more of the following are missing: (a) the complaint does not contain sufficient information (b) the format of the complaint is inconsistent with the requirements of the DMCA (c) the complaint has been submitted via email without proper authentication (d) full contact information is missing. We will need you to re-submit your claim, using the proper format, including sufficient detai, via postal mail or fax. Instructions on how to do so follow.

   No biggie: I just copied and pasted the contents of the email on to a fax sheet and printed it off, but I thought it was funny that I would never have written the DMCA complaint in an email if they didn’t ask for it. And my email did contain all the information, but you can’t trust a computer to do your reading for you in 2009.
   I just hope my fax doesn’t get sent back telling me to put it in the snail mail now!

PS.: I might have had a bit of fun at Hostgator’s expense, but I have to hand it to them: they acted within hours and removed the infringer’s website. Well done.